A dynamic range of an image shot by a digital still camera, a digital video camera, and the like having a solid-state image sensor such as a CCD and so on is far narrower than a dynamic range of an image shot by a traditional silver-halide camera using a silver-halide photography film. In a case where the dynamic range is narrow, “an underexposure” occurs in a dark area of a photographic subject and “an overexposure” occurs in a bright area of the photographic subject, and thereby an image quality is degraded.
In order to expand the dynamic range of the image shot by the solid-state image sensor such as the CCD and so on, for example, Japanese patent publication No. 2000-92378 discloses a technique in which a plurality of shootings is performed with different exposure amounts on the same photographic subject, a plurality of different exposure-amount images is obtained, and then these images are put together to produce a composite image with an expanded dynamic range.